TY - JOUR

T1 - Time–Frequency Analysis of Variability in External Respiration and Heart Rate in Humans during Exercise

AU - Grishin, V. G.

AU - Grishin, O. V.

AU - Nikultsev, V. S.

AU - Gultyaeva, V. V.

AU - Zinchenko, M. I.

AU - Uryumtsev, D. Yu

N1 - Funding Information: This work was supported by the program of basic research of the Russian Academy of Sciences (project nos. 122010800028-4 (United National Information Filing System) and AAAA-A21-121011990040-8). Publisher Copyright: © 2022, Pleiades Publishing, Inc.

PY - 2022/8

Y1 - 2022/8

N2 - Abstract: Very low frequency (VLF) oscillations in parameters of the oxygen transport system (OTS) were studied at rest and during light physical exercise on a bicycle ergometer. Nine healthy subjects (five males and four females) aged 26–58 years participated in the study. The following indicators were recorded by the breath-by-breath method in a 30-min test: end-tidal oxygen, end-tidal carbon dioxide, respiratory rate, and tidal volume. The heart rate was simultaneously recorded using a PoliSpectr 8 ECG system. Pulmonary gas exchange was assessed by the rate of O2 absorption from the inhaled air. The intensity of pulmonary gas exchange during exercise was three times higher than at rest. Time–frequency analysis was used to study quasi-periodic oscillations. The results confirmed the stability of periodic oscillations in the VLF range during physical exercise. Exercise increased the frequency characteristics of all OTS parameters by 28–63%. The variability in the VLF range persisted in spite of the fold increase in the mean values of external respiration and metabolic parameters and the additional effect of cyclic exercise on a bicycle ergometer. The results confirm the hypothesis that synchronization of slow oscillations of RR intervals in the ECG signal with oscillations in pulmonary ventilation and gas exchange signals is a regular phenomenon. The respiratory and circulatory systems were assumed to form a united cyclic circuit of autoregulation (self-organization), the system-forming function of which is to support metabolism at the cell level or the level of the whole human body.

AB - Abstract: Very low frequency (VLF) oscillations in parameters of the oxygen transport system (OTS) were studied at rest and during light physical exercise on a bicycle ergometer. Nine healthy subjects (five males and four females) aged 26–58 years participated in the study. The following indicators were recorded by the breath-by-breath method in a 30-min test: end-tidal oxygen, end-tidal carbon dioxide, respiratory rate, and tidal volume. The heart rate was simultaneously recorded using a PoliSpectr 8 ECG system. Pulmonary gas exchange was assessed by the rate of O2 absorption from the inhaled air. The intensity of pulmonary gas exchange during exercise was three times higher than at rest. Time–frequency analysis was used to study quasi-periodic oscillations. The results confirmed the stability of periodic oscillations in the VLF range during physical exercise. Exercise increased the frequency characteristics of all OTS parameters by 28–63%. The variability in the VLF range persisted in spite of the fold increase in the mean values of external respiration and metabolic parameters and the additional effect of cyclic exercise on a bicycle ergometer. The results confirm the hypothesis that synchronization of slow oscillations of RR intervals in the ECG signal with oscillations in pulmonary ventilation and gas exchange signals is a regular phenomenon. The respiratory and circulatory systems were assumed to form a united cyclic circuit of autoregulation (self-organization), the system-forming function of which is to support metabolism at the cell level or the level of the whole human body.

KW - gas exchange variability

KW - heart rate variability

KW - oxygen transport system

KW - quasi-periodic oscillations

KW - ventilation variability

UR - http://www.scopus.com/inward/record.url?scp=85140257763&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/413ba321-711a-32f7-82a4-e45d2a724d6d/

U2 - 10.1134/S0006350922040091

DO - 10.1134/S0006350922040091

M3 - Article

AN - SCOPUS:85140257763

VL - 67

SP - 605

EP - 611

JO - Biophysics (Russian Federation)

JF - Biophysics (Russian Federation)

SN - 0006-3509

IS - 4

ER -